Topic/Type: 1.5 Low-temperature, dusty and nano-plasmas, Oral
M. M. Hopkins1, P. S. Crozier2, T. P. Hughes1, J. J. Boerner2
1 Nanoscale and Reactive Processes, Sandia National Laboratories, Albuquerque, New Mexico, USA
2 Multiscale Dynamic Materials Modeling, Sandia National Laboratories, Albuquerque, New Mexico, USA
In this talk we will give a brief description of our low temperature plasma simulation tool, Aleph, and its application to modeling vacuum arc discharges. Aleph is a three-dimensional parallel PIC/DSMC electrostatic plasma simulation tool employing unstructured meshes. It has been used to simulate colliding and reacting neutral and ionized species in complex three-dimensional geometries. Following a short description of Aleph, we will discuss our investigations into simulating vacuum arc discharge. Here, we simulate breakdown between a virtual cathode (extracting electrons from a bulk plasma) and a time-varying anode source of neutrals. Our anode model incorporates energy deposition due to electron bombardment, temperature history, and neutral emission rates. Because the number densities of the electrons, neutrals, and ions vary greatly in time and space we have implemented a new particle weighting scheme based on keeping the number of particles for each species in each cell fixed. That is, each cell\'s weight for a species varies over time according to the temporal and spatial evolution of the simulation. We will describe the efficiency gains by implementing this reweighting scheme and identify some of its current shortcomings.